Fuel indicator



Feb. 16, 1943- 'r. H. SVENDSEN FUEL INDICATOR 4 Filed July 16, 1940 MIN fad/923W? dig Z5 Patented Feb. 16, 1943 UNITED STATES PATENT OFFICE FUEL INDICATOR Trygve H. Svendsen, Chicago, 111.

Application July 16, 1940, Serial No. 345,863

17 Claims.

My invention relates to fuel indicators of the type described in my pending patent application filed December 11, 1939, under Serial No. 308,719, of which this application is a continuation in part and deals more particularly with a transfer chamber connected with an automobile fuel tank.

One object of the improved fuel transfer chamber is to include means for rendering the action of the chamber more definite than heretofore.

Another object of the improvement is to so apply the air and fuel conduits to the transfer chamber that the fall of fuel to a certain level will remove it from the path of the air supply to the chamber, so that the change from a fuel feed to an air supply will be definite.

With the above objects in view and any others which may suggest themselves from the description to follow, a better understanding of the improvement may be had by reference to the accompanying drawing, in which- Fig. 1 is a front elevation of the fuel tank, showing the application of the improvement;

Fig. 2 is an enlargement of the central portion of Fig. 1;

Fig. 3 is a section on the line 3-3 of Fig. 2;

Fig. 4 is a section on the line 4-4 of Fig. 1, showing a lever swung to a vertical position; and

Fig. 5 is a vertical section of a valve in the left-hand portion of Fig. 4.

Referring specifically to the drawing, is denotes the fuel tank of an automobile or other vehicle from which the fuel is drawn by suction to the carburetor of the engine. While the conventional fuel line is taken directly from the tank, the present improvement requires that such fuel line be divided into inner and outer sections H and 12.

As indicated in Fig. 3, the fuel line section II rises obliquely from the bottom of the tank l and terminates in the front wall thereof, opening into a chamber l3 which is applied to the outer side of the said wall. The outer wall of the chamber I3 is extended above the center as indicated at I4 to provide a receptacle for the outer section [2 of the fuel line. The position of this receptacle is such as to offset the section l2 of the fuel line from the section I thereof.

The chamber 13 is preferably circular and is formed with a flange I at its mouth, such flange being soldered or brazed to the front wall of the tank H) in order to make a sealed closure therewith. The circular wall lli of the chamber l3 is extended at one side with a socket ii to receive one end of the air-supply line It, the position of the socket being somewhat below the center line of the chamber.

The air-supply line I 8 leads upwardly along the front wall of the tank to a point suitable for a bend l9 to locate the upper end of the line alongside the filler neck 20 of the tank. Similarly to the showing in my said application, the upperend of the air-supply line receives a rotary valve 2| which may be of the plug type shown in Fig. 5-and whose handle 22 normally extends in a horizontal position to indicate that the valve is open. The handle 22 terminates with a side flange 23. The filler neck 20 receives a conventional cap 24, and the handle 22 of the valve 2| is so designed that the flange 23 may closely overlie the cap 24 when the handle is swung to a vertical position, as shown in Fig. 4. Thus, in order to remove the cap the handle would have to be swung to the horizontal position.

When the tank It contains a sufficient supply of fuel, the same is drawn into the fuel line section H, through the chamber l6 and into the fuel line section l2 by the suction from the engine pump. The air-supply line I8 is of course open at its upper end and contains fuel which falls as the fuel in the tank is being used. However, when the fuel level in the tank Iii falls to a point below the entrance of the air line 18 into the chamber l3, it follows that the suction in the line I2 will draw more readily on the air admitted into the upper part of the chamber from the air line I8, so that only air instead of fuel will pass to the engine pump, and the engine will stop running.

The above circumstance is a warning to thedriver that the fuel in the tank 10 has dropped to a predetermined low level, and that the fuel must be replenished. However, the automobile may be driven with the residue fuel until a supply station is reached, this being accomplished by swinging the handle 22 up to the position where its flange 23 overlies the cap 24. Now the supply of air to the chamber I3 is cut off, and when the engine is again started the suction in the fuel said application, the particular values in the im-' provement are of importance. Thus, the first advantage of the improved chamber is that it is entirely external of the tank. This enables the chamber to be attached to any fuel tank, either during the process of building the automobile or for the equipment of any new or used automobile with the novel fuel indicator. For this purpose, it is only necessary to drill a small hole in the front wall of the tank at a low point, as indicated at 25 in Fig. 3, and to solder or otherwise install the inner fuel line section I I in a manner to open to the exterior. Now the chamber 53 is simply applied in the manner of a cup to the front wall of the tank and marginally soldered or brazed to make a sealed connection therewith. The fuel line section I2 and air line I8 are fitted to the chamber beforehand or after its installation, also being suitably sealed into their respective receptacles I4 and I1. With the device installed as in Fig. 1, the leading of the fuel line I2 It will be evident from the above description that the construction of the improved transfer chamber I3 has values which are peculiar and of important functional advantage to define the operation of the low fuel level indicator, so that the driver readily gains the knowledge thereof instead of suspecting the behavior of the engine. Also, with a predetermined fuel reserve under all driving conditions the benefit of most of the tank contents will be had before the low-level indication occurs; and in this event the knowledge that only a small reserve is availablejust enough to tide over the emergency, such as a gallon of fuelthe driver will of course quickly adjust the handle 22 in the manner described to enable him to proceed on his way until a supply station is to the engine pump places the device in readiness for use in the manner described.

It is significant that the entrance of the air line I8 into the chamber I3 is at a relatively low point, so as to keep such entrance from becoming uncovered during the regular operation of the automobile until the very tim that the low fuel level point is reached. At this juncture, the admission of air is facilitated by the ofiset position of the fuel line sections II and I2, since the section I2 will have access to the air from the air-line inlet more readily than to the out-of-line fuel stream entering from the low or offset fuel line section II, so that a radical interruption of the fuel stream to the fuel line section I2 will occur, breaking off the flow. This action is in contrast to that in the Wattells patent mentioned in my said application, where I have found that the performance of the device varies with the rate of fuel suction. Thus, when the engine runs slowly the fall of the fuel in the Wattells chamber soon allows an air gap or clearance across the entrances of the air and engine fuel supply pipes and the engine will draw air and come to a stop while a considerable amount of fuelfar more than is needed as a reserve-still remains in the tank. On the other hand, speeding up the engine draws on the fuel in the Wattells chamber so rapidly that its level will fall to a low point in the chamber before a sufficient air gap or preponderance is created to break the fuel supply to the suction line. Thus, during the normal operation of an automobile with the Wattells device the driver cannot tell whether he has a high or low fuel reserve. However, by placing the entrance of the suction line I2 of the instant improvement some distance below the top of the chamber I3, the fuel level is given a chance to fall into the lower part of the chamber before it can uncover the entrance to the air pipe I8. During the fall a partial vacuum forms in the upper part of the chamber, tending to keep up the communication of the fuel to the suction pipe I2. Thus, irrespective of the speed of the engine and the tendency of the fuel to climb toward the suction pipe I2, the actual fuel level falls and only breaks communication with the path from the tank pipe I I when the level in the chamber is quite low, or about even with the top of the entrance to the tank pipe. The offset of this pipe from the suction pipe helps, when the fuel has reached the lowest level, to keep it clear of'the entrance to the air pipe I8. This action has the effect of stopping the engine promptly instead of allowing the same to struggle or sputterover a dwindling fuel supply for some time.

reached. In this respect the low position of the suction pipe entrance in the chamber I6 will facilitate the pick-up of reserve fuel without the prolonged use of the engine starter. This is because the body of air which is inevitably trapped in the chamber is located above the point at which the fuel line opens into the chamber whereby the end of the fuel line is submerged. Despite this important function, the improved transfer chamber is of utmost simplicity and has no parts of a moving or delicate character to require attention or get out of order. The fact that the flange 23 of the handle 22 overlies the cap 24 assures the restoration of the handle to the normal position before the station attendant can remove the cap for re-filling the tank, so that the air line is reopened without fail when the fuel is replenished, and the indicator is automatically restored to normal operation.

Obviously the sizes of the fuel pipes, air tube and chamber may vary in different power plants and under different conditions. However, generally speaking the air tube should be larger than either of the fuel pipes to insure a break in the fuel feed. Thus, Where the fuel pipes II and I2 are up to A," in diameter, the air tube should be 1- -6" in diameter or larger. In like manner under these conditions the chamber I6 should not be smaller than 1 /2" in internal diameter. Obviously the size of the chamber I 6 must increase as the size of the fuel pipes increases.

While I have described the improvement along specific lines, various minor changes and refinements may be made without departing from its principle, and I desire to consider all such changes and refinements as coming Within the scope and spirit of the appended claims.

I claim:

1. The combination of an engine, a fuel tank therefor with a perforation in the lower portion of one of its walls, an internal pipe rising from a point close to the bottom of the tank to meet said Wall and communicate with the outside thereof by way of said perforation, a cup-shaped chamber with its rim secured to the outside of said wall and with its lower portion opposite said perforation, a suction pipe leading from the chamber to the engine, an air-supply tube leading to the chamber, and means to control the airsupply tube.

2. The structure of claim 1, said suction pipe leading from the outer wall of the chamber.

3. The structure of claim 1, said suction pipe leading from the outer wall of the chamber and in offset relation to said internal pipe.

4. The structure of claim 1, said suction pipe leading from the outer wall of the chamber and in offset relation to said internal pipe, said internal pipe extending obliquely, and said section pipe also having its initial portion in an oblique course, such portion being substantially parallel to the internal pipe and offset from the same.

5. The structure of claim 1', said suction pipe leading. from the outer wall of the chamber and in offset relation to said internal pipe, said internal pipe extending obliquely, and said suction pipe also having its initial portion in an oblique course, such portion being substantially parallel to the internal pipe and offset from the same in an upward direction.

6. The structure of claim 1, said suction pipe commencing at a point considerably higher than the entrance of the internal pipe into the chamber with a view to creating a cross-current in the fuel communicating with the chamber by way of said internal pipe, and said air-supply tube entering the chamber at a point to direct air in the path of said current in response to the suction when the fuel level in the chamber becomes W.

'1. The structure of claim 1, said suction pipe commencing from the outer wall of the chamber, and the air-supply tube leading to a side wall thereof.

8, The structure of claim 1, said suction pipe commencing from the outer wall of the chamber, and the air-supply tube leading to a side wall thereof to enter the chamber at, a point in the lower portion thereof.

9. The structure of claim 1, said internal and suction pipes having inclined courses with the suction pipe offset from the internal pipe in an upward direction, and said air-supply tube entering the chamber by way of a side wall thereof and in a direction to supply air into the path of fuel drawn into the suction pipe.

10. The structure of claim 1, a filler neck for said tank, and a closure for the filler neck, said means being a valve normally open and having a portion movable to lie in the opening path of and be held closed by said closure.

11. The structure of claim 1, a filler neck for said tank, and a closure for the filler neck, said air-supply tube terminating at point alongside the filler neck, and said means comprising a valve for the tube and normally open, a handle for the valve and substantially horizontally positioned when the valve is open, the valve being closable by swinging the handle to a substantially upright position, and a side flange carried by said handle and positioned to overlie said closure when the handle is in the vertical position, whereby to prevent the opening of the closure.

12. The combination of an engine, a fuel tank therefor, a closed fuel level indicator chamber adjacent to the bottom of said tank and havin a pipe leading into the tank, an air supply tube in normally open communication with the atmosphere and opening into said chamber at a point at least partly above the point of entry of said fuel pipe, a second fuel pipe connecting said chamber to the suction line of the engine and opening into said chamber at a point substantially below the top thereof and at least partly above the point of entry of said air supply tube, and means for closing the latter at times.

13. A fuel indicator for a power plant including an internal combustion engine and a fuel tank therefor; comprising an indicator chamber on a wall of said tank intermediate the top and bottom of said tank, said chamber being formed by a wall portion of said tank and by a separate member secured thereto, a suction pipe leading from said chamber to the engine, a second suction pipe leading from the bottom of said tank to said chamber, a normally open air supply tube having one end opening into said chamber and a free end exposed to the atmosphere, means for opening and closing said tube, said tank having a filling opening and a closure cap therefor, said tube leading from said chamber to a point outwardly of said tank and closely adjacent said cap, said means for opening and closing said tube being a valve located substantially at the free end of said tube and including movable means engageable with said cap when said valve is closed to prevent the normal removal of said cap from said opening but movable out of engagement with said cap when said valve is opened.

14. A fuel indicator for a power plant including an internal combustion engine and a fuel tank therefor; comprising an indicator chamber on a wall of said tank intermediate the top and bottom of said tank, said chamber being formed by a wall portion of said tank and by a separate member secured thereto, a suction pipe leading from said chamber to the engine, a second suction pipe leading from the bottom of said tank to said chamber, a normally open air supply tube having one end opening into said chamber and a free end exposed to the atmosphere, means for opening and closing said tube, said tank having a filling opening and a closure cap therefor, said tube leading from said chamber to a point outwardly of said tank and closely adjacent said cap, said means for opening and closing said tube be ing a valve located substantially at the free end of said tube, and including a handle for opening and closing the valve, said handle being engageable with said cap when said valve is closed to prevent normal removal of said cap but being movable out of engagement with said cap when said valve is open.

15. A fuel indicator for a power plant including an internal combustion engine and a fuel tank therefor; comprising an indicator chamber on a wall of said tank intermediate the top and bottom of said tank, said chamber being formed by a wall portion of said tank and by a separate member secured thereto, a suction pipe leading from said chamber to the engine, a second suction pipe leading from the bottom of said tank to said chamber, a normally open air supply tube having one end opening into said chamber and a free end exposed to the atmosphere, means for opening and closing said tube, said tank having a filling opening and a closure cap therefor, said tube leading from said chamber to a point outwardly of said tank and closely adjacent said cap, said means for opening and closing said tube being a valve located substantially at the free end of said tube, and including a handle for opening and closing said valve, said handle having a portion adapted to overlie said cap in engagement therewith to prevent normal removal of said cap when said valve is closed, said handle portion being adapted to clear said cap when said handle is moved to a position 'to open said valve.

15. A fuel indicator for a power plant including an internal combustion engine and a fuel tank therefor; comprising an indicator chamber on a wall of said tank intermediate the top and bottom of said tank, said chamber being formed by a wall portion of said tank and by a separate member secured thereto, a suction pipe leading from said chamber to the engine, a second suction pipe leading from the bottom of said tank to said chamber, a normally open air supply tube having one end opening into said chamber and a free end exposed to the atmosphere, means for opening and closing said tube, said tank having a filling opening and a closure cap therefor, said free end of said tube being located adjacent said cap, said means for opening and closing said tube being manually closable and operative at said free end thereof and including means associated with said cap and normally requiring said tube to be open when said cap is removed from said opening.

17. A fuel indicator for a power plant including an internal combustion engine and a fuel tank therefor; comprising an indicator chamber on a wall of said tank above the floor thereof, a suction pipe leading from the bottom of the tank into the bottom portion of said chamber, a second suction pipe connecting said chamber to th engine, a normally open air supply tube connecting said chamber with the atmosphere, and said tube and said second suction pipe opening into said chamber above the point where the first suction pipe opens into said chamber but a substantial distance below the top of said chamber to provide a closed air space of substantial size in said chamber above the points of entry thereinto of said tube and said second suction pipe, and means for opening and closing said tube.

TRYGV'E H. SVENDSEN. 

